DESCRIPTION (Unedited Applicant's Abstract): The intrathoracic compliance chamber (ICC) is the most successful solution to the variable volume problem of a totally implantable pulsatile artificial heart. However, existing designs are handicapped by the rate at which the gas permeates through the chamber diaphragm given that all polymeric membranes are subject to some degree of gas permeation. Given this limitation, percutaneous gas refills would be required at frequent intervals, measured at best in weeks. It is Foster-Miller's hypothesis that this limitation can be remedied by the use of liquid crystal polymers (LCPs), a material of remarkable mechanical performance and extremely low permeability. In the Phase I program, Foster-Miller demonstrated that LCPs have the biocompatibility, low permeability, high fatigue resistance and sufficient manufacturability to be ideal candidates for ventricular assist devices (VAD) and total artificial heart (TAH) compliance chamber diaphragms. The proposed Phase II program will demonstrate the long-term performance and stability of an integrated compliance chamber system. Pilot manufacturing techniques will be developed and components manufactured with these techniques will be evaluated both in-vitro and in-vivo. The long-term objective of this project is to design, develop, and qualify a compliance chamber system that can be integrated with existing and future blood pumps to make truly implantable systems. PROPOSED COMMERCIAL APPLICATION: The primary market for the proposed product is represented by the 35,000 to 70,000 patients per year estimated by the Institutes of Medicine to require permanent ventricular assist devices or total artificial hearts. This market could be even larger when blood- pumping systems are proven to be safe enough to use in more than the very sickest, near-terminal patients.